Understanding Floating Stemcells

This topic describes how floating stemcells work in Pivotal Cloud Foundry (PCF) and the consequences for upgrading product tiles in Ops Manager.

Floating Stemcell Benefits

Floating stemcells have the following benefits:

PCF can quickly propagate a patched stemcell to all virtual machines in the deployment when a vulnerability is discovered.

Operators can perform certain deployment-wide updates, such as CVEs, by uploading a new stemcell instead of uploading .pivotal files for each tile, which reduces the time spent waiting for files to upload.

Stemcell Major and Minor Upgrade Limitations

Floating stemcells allow upgrade to the minor versions of stemcells but not the major versions.

For example, a stemcell can float from 1234.56 to 1234.99 but not from 1234.991 to 1235.0.

Product Tile Upgrades

When an operator upgrades a product tile, Ops Manager performs the following steps:

Ops Manager checks to see whether a new minor, or patch, version of the stemcell exists.

If a minor stemcell is available from the current major line, Ops Manager installs the upgraded tile and all compatible product tiles in the deployment on the new stemcell.

Uploading and Managing Stemcells

Operators can upload new stemcells to their product tiles by using the Ops Manager API or by using the Stemcell Library in the Ops Manager Installation Dashboard. For more information about the Stemcell Library, see Importing and Managing Stemcells.